Phonon Spectra of a-SiNx: H/Si Heterostructures Observed by Brillouin Light Scattering

Low-frequency phonon spectra in a-SiNx: H/Si heterostructures have been observed by means of Brillouin light scattering. Measurement of the frequency shift on longitudinal and transverse acoustic phonons as well as on surface phonons enabled us to extract accurately two independent elastic moduli: c11 and c44 deduced from phase velocities of bulk acoustic modes and scattering wavevector, within effective medium approximation.